With the deployment of third generation cellular systems, operators will be able to provide an extensive number of data services to cellular subscribers. With these new data services, each subscriber will be competing for both signalling channels along with fundamental and supplemental traffic channels (hereinafter referred to together as traffic channels) for bulk data transfers based on user profile privileges. This increase in demand for bandwidth will result in a decrease in available network resources and potentially an increase in the occurrences in which insufficient bandwidth is available for all connections within a particular sector and/or cell.
When a mobile terminal travels from a first coverage area to another coverage area, a competition for network resources may occur. The nature of the CDMA frequency reuse assumes an equal distribution of mobile terminals throughout the service area. However, in reality, unequal call loading frequently occurs, thus possibly causing a mobile terminal to have little choice but to drop its connection. If the mobile terminal is operating within a packet data session at the time its wireless connection is dropped, the packet data session will also be disconnected.
The establishment of data packet sessions require considerable signalling and the time required to re-establish a packet data session is inconvenient for customers. Thus, any technique to avoid the need to re-establish packet data sessions is important.
As currently designed, the handoff algorithms defined within standards and implemented within products currently utilized for voice communications are continuing to be used for the transmission of data packets. Unfortunately, data packet traffic and voice communications have different operating parameters that make the use of a common handoff technique potentially inefficient.
Hence, a new hard handoff technique is needed that takes advantage of the unique characteristics of packet data transmissions such that the need to re-establish a data packet session in cases of insufficient network resources (eg. overloaded cells/sectors) is reduced.